Ultrasonography in Pregnancy: Complete Guide to Scans from Early Pregnancy to Delivery
Updated: Aug 24
Pregnancy is a journey filled with important milestones, and ultrasonography in Chennai plays a key role in monitoring the health and development of your baby. Pregnancy ultrasound scans allow doctors to assess fetal growth, development, anatomy, position and, when required, blood flow.
But how many pregnancy scans do you actually need? When should you have them? And what does each scan check?
This complete guide explains the common types of pregnancy ultrasonography, from early pregnancy through the later stages of pregnancy.
What Is Ultrasonography in Pregnancy?
Ultrasonography in pregnancy uses high-frequency sound waves to create images of the developing baby and reproductive organs. It does not use X-rays or ionising radiation.
Depending on the stage of pregnancy and your individual needs, your doctor may recommend different ultrasound examinations.
A pregnancy ultrasound can help assess:
Gestational age and fetal development
Fetal heartbeat
Number of babies
Fetal growth
Placental location
Amniotic fluid
Fetal anatomy
Cervical length when indicated
Blood flow using Doppler when clinically required
The timing and type of scan can vary depending on your pregnancy history, symptoms and clinical requirements.
When Is the First Pregnancy Ultrasound Done?
An early pregnancy ultrasound may be recommended during the first trimester. It can help confirm the location of the pregnancy, assess fetal viability and estimate gestational age.
A dating scan may be particularly useful when menstrual dates are uncertain or when your doctor needs an ultrasound-based assessment of gestational age.
In some cases, an early scan may also help identify whether there is more than one pregnancy.
What Is a First-Trimester or NT Scan?
The first trimester is an important period for assessing fetal development.
An NT scan, or nuchal translucency scan, measures the fluid collection at the back of the fetal neck. It is commonly performed as part of first-trimester screening for certain chromosomal conditions.
The ultrasound assessment may be combined with maternal blood tests as part of a broader screening strategy.
It is important to remember that screening does not provide a definite diagnosis. A higher-risk screening result may lead to further counselling or testing.
What Is the Anomaly Scan?
The anomaly scan, also called a detailed fetal structural or Level II ultrasound in some settings, is one of the most important pregnancy scans.
It is generally performed during the second trimester and involves a detailed examination of the baby's anatomy.
The specialist may assess structures such as:
Brain and skull
Face
Spine
Heart
Abdomen
Kidneys
Limbs
Placenta
Amniotic fluid
The scan is designed to identify structural abnormalities and assess fetal development. However, no ultrasound can detect every possible condition.
According to the NHS, the 20-week screening scan examines the baby's physical development and checks for certain structural conditions.
What Is a Fetal Echocardiography Scan?
A fetal echocardiography is a specialised ultrasound examination of the baby's heart.
It provides a more detailed assessment of cardiac structures and blood flow than a routine pregnancy ultrasound.
Your doctor may recommend fetal echocardiography when there is a particular risk factor, an ultrasound finding that requires further evaluation, or another clinical reason to examine the fetal heart in greater detail.
What Is a Growth Scan?
As pregnancy progresses, your doctor may recommend a fetal growth scan to assess how your baby is growing.
The scan may measure parameters such as:
Head size
Abdominal circumference
Femur length
Estimated fetal weight
Amniotic fluid
Placental assessment
Growth scans may be particularly useful when there are concerns about fetal growth or other pregnancy-related factors.
What Is a Doppler Scan in Pregnancy?
Doppler ultrasound is used to assess blood flow through specific blood vessels.
It may be recommended when your doctor needs additional information about placental function, fetal circulation or fetal wellbeing.
Doppler assessment is not necessarily required in every pregnancy. It should be performed when clinically indicated and interpreted in the context of the complete pregnancy assessment.
Is Pregnancy Ultrasonography Safe?
Ultrasound has been widely used in obstetric care for many years. Unlike X-rays, ultrasound does not use ionising radiation.
However, pregnancy ultrasound should still be performed for appropriate medical reasons and by trained professionals. The AIUM recommends that diagnostic ultrasound examinations be performed prudently and according to the clinical indication.
How to Choose an Ultrasonography Centre in Chennai?
If you are looking for ultrasonography in Chennai, consider more than just the availability of an ultrasound machine.
Look for:
Qualified and experienced specialists
Appropriate pregnancy ultrasound protocols
Advanced imaging facilities
Detailed and understandable reports
Access to fetal medicine expertise when required
Proper counselling when an abnormality is suspected
Coordination with your obstetrician
Most importantly, the scan should be selected according to your pregnancy and medical requirements rather than simply choosing the most advanced scan available.
Conclusion
Pregnancy ultrasonography provides valuable information at different stages of pregnancy, from confirming early development to assessing fetal anatomy, growth and wellbeing.
There is no single ultrasound schedule that is identical for every woman. Your obstetrician or fetal medicine specialist can recommend the appropriate scans based on your gestational age, medical history and pregnancy needs.
If you are searching for Ultrasonography Chennai, choose a centre where accurate imaging is combined with specialist expertise, careful interpretation and clear communication.
Doctor’s Note
“Ultrasound is an important part of pregnancy care, but every scan has a specific purpose. The timing and type of ultrasound should be decided according to the individual pregnancy rather than following a one-size-fits-all approach. A detailed discussion with your obstetrician or fetal medicine specialist can help you understand which scans are appropriate and what the results mean for you and your baby.”
— Dr. Divya Ravikumar, MBBS, DNB (OG), MRCOG, PDF (Fetal Medicine), Fetal Medicine Specialist
FAQs
1. How many ultrasound scans are needed during pregnancy?
There is no fixed number of scans required for every pregnancy. The number and timing depend on factors such as gestational age, medical history, pregnancy risk factors and any findings during previous examinations.
2. When is the anomaly scan performed?
The detailed anomaly or structural scan is generally performed during the second trimester, commonly around 18–22 weeks. Your doctor will recommend the appropriate timing based on your pregnancy.
3. Is ultrasound safe during pregnancy?
Diagnostic ultrasound does not use ionising radiation and is widely used during pregnancy. It should be performed by appropriately trained professionals for a medical indication.
4. What is the difference between a growth scan and an anomaly scan?
An anomaly scan focuses primarily on detailed assessment of fetal anatomy and structural development. A growth scan primarily evaluates fetal growth and related parameters. Your doctor may recommend one or both depending on your pregnancy.
5. Where can I get ultrasonography in Chennai?
You can look for a pregnancy ultrasound or fetal medicine centre in Chennai that has experienced specialists, appropriate imaging facilities, detailed reporting and counselling support. The right centre should be selected based on the type of scan you require and your individual pregnancy needs.
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